1. Field of the Invention
The present invention relates to a microwave oven having a browning device. In particular, the present invention relates to a microwave oven having a browning device comprising a grill element that is arranged to radiate infrared radiation towards a foodstuff placed in the oven.
2. Description of the Related Art
In microwave ovens, browning devices of various kinds are often incorporated in order to allow cooking or heating of food in such a way that a crusty surface is obtained on the foodstuff, i.e. such that a browning effect is achieved. Radiant heat is produced by a tube radiating infrared (IR) radiation (e.g. a quartz tube). The infrared radiation (the thermal exposure) falling on the foodstuff is, in some prior art ovens, increased by means of a reflector that is arranged above/behind the radiating tube.
One problem encountered in connection with this kind of browning devices is that the reflector eventually becomes contaminated by splashes from food and the like during cooking, such that the aesthetic appearance of the browning device gets unpleasant and the reflectivity is lowered, leading to decreased browning performance. Hence, both from a technical point of view, and from a commercial point of view, this is problematic.
EP 0 956 739 discloses a microwave oven having a grilling device that is arranged in a hollow space in the ceiling of the oven cavity. The hollow space is designed so that it is essentially free of microwave radiation, and has a connection opening to the oven cavity. The hollow space has walls that are designed to reflect IR radiation and direct said radiation into the oven cavity. A grate is arranged in the area of the connection opening, the grate consisting of a metal sheet having a number of slots. The grate can be arranged to absorb some of the IR radiation from the grilling device in order to provide a high temperature zone. In this way, the temperature of the grate is said to be increased such that splashes from a foodstuff placed in the oven cavity are burnt at the grate, thus preventing contamination of the reflective interior walls of the hollow space.
A hollow space in any wall of a microwave cavity can be designed so that it is essentially microwave free, as disclosed, for example, in EP 0 573 750.
However, the use of a grate as disclosed in EP 0 956 739 leads to lowering of the amount of infrared radiation reaching the foodstuff in the oven cavity, thus reducing the browning efficiency.
Moreover, there is still a considerable risk of contamination of the reflective surface behind the grilling device. Once contamination has reached and stuck to the reflective surface, it is very difficult to make it clean and revive the reflective properties.
Hence, there is a need for new and improved browning devices for which these problems are eliminated.